The abuse of drugs is a problem of every increasing severity. Especially in hospitals and other medical facilities where abusable drugs such as narcotics are stored, this problem is of great concern to the medical community.
One aspect of this problem relates to the outright theft of narcotics by those only peripherally connected with the hospital. This problem can be prevented in large part by the strict security measures which are currently employed anywhere that abusable drugs are stored.
A more insidious aspect of this problem, however, is the surreptitious use of these drugs by medical personnel themselves. The proximity to and familiarity with abusable drugs can cause considerable temptation and lead to unfortunate results.
Such results can occur even more readily with pre-filled syringes then with the customary bottles and ampoules. For example, a pre-filled syringe of an abusable drug may be surreptitously used by a drug abuser and the syringe thereafter completely or partially filled with a foreign fluid (e.g., sterile saline). Aside from the evils which flow from drug abuse, this practice poses significant medical hazards for the patient since not only is the used syringe in an unsterile condition, but it also contains less active ingredient than it should. In a conventional syringe pre-filled with an abusable drug, there is no way of detecting the tampering and hence such conventional pre-filled syringes have generally not been used for abusable drugs.
Recognizing the problem with abuse of injectable drugs, several U.S. patents have addressed the problem by disclosing self-destructible syringes which render themselves unreusable. Examples of such U.S. patents are Geiger U.S. Pat. No. 4,121,588 and Chiquiar-Arias U.S. Pat. Nos. 3,667,657; 3,951,146; and 3,998,224. These syringes all share the property of either destroying themselves or being readily destroyable after use so that the syringes may not be reused for the injection of abusable drugs. These patents do not, however, address the problem of surreptitious injection of a portion of the substance contained in a pre-filled syringe, followed by the introduction of a foreign substance to disguise this use. In fact, these patents are not concerned with the problem of pre-filled syringes at all, because of their focus on destruction of the syringe after use.
Several U.S. Patents have addressed the problem of preventing removal of materials from pre-filled syringes.
For example, Sarnoff U.S. Pat. No. 3,126,004 discloses an improved syringe cartridge constructed to clearly disclose any removal and replacement of the piston, penetration thereof, or sliding of a needle between the piston and the glass wall of the cartridge to effect removal of cartridge contents. Sarnoff accomplishes this objective by placing a colored sealing wax material over the outer surface of the piston, which material would be disturbed if the piston were removed or which would be transferred into the cartridge if a needle were introduced between the piston and the cartridge.
While this method may indeed prevent tampering with the pre-filled syringe, this solution to the problem is a messy and complicated one which has not been put into practice in the almost twenty years since issue of this patent.
A second example in the art of attempts to prevent tampering with pre-filled syringes is Hobbs U.S. Pat. No. 3,666,113 in which (as in Sarnoff) the piston end is coated by a material. In contrast to Sarnoff, however, the material used in Hobbs is a thin layer of flexible plastic material which may optionally have a fluorescent dye imprint on it. Hobbs draws attention to the defects of the Sarnoff patent relating particularly to the brittleness of the sealing wax coating which could easily occur as a result of handling or shipping and thus give a false indication of tampering.
Hobbs seeks to solve this problem by employing a flexible plastic material adhering to the exterior surface of the cartridge barrel in the region of the open end so as to cover the piston. While this procedure may remove the difficulties attendant upon the Sarnoff device, it nevertheless is a relatively cumbersome apparatus to use and involves the necessary step of dipping the syringe end into the molten plastic material, which is seen to be a clear disadvantage.
In contrast to these prior art methods for preventing tampering with pre-filled syringes, the subject syringe is simple to construct and use but yet readily prevents surreptitious use and refilling of the syringe.